Gas turbines are subjected to extremes of temperature, resulting in significant amounts of thermal expansion and contraction during a typical gas turbine operation cycle, for example during start-up, cool-down or transition phases. The various parts of a gas turbine tend to change temperature at different rates, due to factors such as size, surface area and level of exposure to hot gases or cooling air. This can cause significant differences in expansion/contraction of adjacent components, and in such circumstances providing a good seal between adjacent components can be a major challenge. One particular area where differing thermal expansion and contraction rates can cause problems is around the first vane of the turbine section of a gas turbine.